Coulomb interaction polar solvents

When electronic excited states in the QM region are considered, each electronic state possesses unique electronic density and thus interacts differently with polarizable environment. Purely electrostatic (Coulomb) interactions between solvent and electronically excited solute are automatically taken into account due to a presence of the one-electron Coulomb term in the QM Hamiltonian (Eq. 5.10). A part of polarization interactions is also represented in a similar way due to an explicit inclusion of EFP induction terms in the QM Hamiltonian, as given by Eq. 5.11. 

To obtain an estimate for the energy of reorganization of the outer sphere, we start from the Born model, in which the solvation of an ion is viewed as resulting from the Coulomb interaction of the ionic charge with the polarization of the solvent. This polarization contains two contributions one is from the electronic polarizability of the solvent molecules the other is caused by the orientation and distortion of the... 

In the case of polar SD, the main change in solute properties is in its charge distribution. If the eharge distributions of the solute and solvent molecules are represented as sets of partial charges, as is usually done in computer simulation studies of SD, A Wp, is a smn of Coulombic interactions... 

The characterization of a solvent by means of its polarity is an unsolved problem since the polarity itself has, until now, not been precisely defined. Polarity can be understood to mean (a) the permanent dipole moment of a compound, (b) its dielectric constant, or (c) the sum of all those molecular properties responsible for all the interaction forces between solvent and solute molecules (e.g., Coulombic, directional, inductive, dispersion, hydrogen bonding, and EPD/EPA interaction forces) (Kovats, 1968). The important thing concerning the so-called polarity of a solvent is its overall solvation ability. This in turn depends on the sum of all-specific as well as nonspecific interactions between solvent and solute. 

In particular, V° describes a solute-solute Coulomb and exchange-correlation interaction corrected by an overlap contribution. The effects of the solvent on V° are implicitly included in the values of the transition properties of the two chromophores before the interaction between the two is switched on. These properties can in fact be significantly modified by the reaction field produced by the polarized solvent. In addition, the solvent explicitly enters into the definition of the coupling through the term VIEF of Equation (3.150), which describes the chromophore-solvent-chromophore interaction. 

Here X, = const is a contribution of an intramolecular mode, while the second term, Xs(r), accounts for the Coulomb interaction with the polarized solvent. The contact value of this term... 

In solvents of low polarity the formation of triple ions and ion quadrupoles with an increasing concentration of ionic salts has been observed [31]. The conductance versus concentration is a function with a minimum. The increase in conductivity versus concentration (after the minimum) is due to the formation of triple ions by coulombic interaction between ion pairs and ionic species. The equation describing this equilibrium is [32]... 

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